CNL-16-118, Response to Request for Additional Information on Proposed Technical Specifications (TS) Change TS-505 - Request for License Amendments - Extended Power Uprate (EPU) - Supplement 27

Response to Request for Additional Information on Proposed Technical Specifications (TS) Change TS-505 - Request for License Amendments - Extended Power Uprate (EPU) - Supplement 27

ML16211A393
Person / Time
Site:	Browns Ferry
Issue date:	07/29/2016
From:	James Shea Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNL-16-118
Download: ML16211A393 (14)

Text

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-16-118 July 29, 2016 10 CFR 50.90 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Units 1, 2, and 3 Renewed Facility Operating License Nos. DPR-33, DPR-52, and DPR-68 NRC Docket Nos. 50-259, 50-260, and 50-296

Subject:

Proposed Technical Specifications (TS) Change TS-505 - Request for License Amendments - Extended Power Uprate (EPU) - Supplement 27, Response to Requests for Additional Information

References:

1. Letter from TVA to NRC, CNL-15-169, "Proposed Technical Specifications (TS) Change TS-505 - Request for License Amendments - Extended Power Uprate (EPU)," dated September 21, 2015 (ML15282A152)

2. Letter from NRC to TVA, Browns Ferry Nuclear Plant, Units 1, 2, and 3 -

Request for Additional Information Related to License Amendment Request Regarding Extended Power Uprate (CAC Nos. MF6741, MF6742, and MF6743), dated July 21, 2016 (ML16187A293)

3. Letter from TVA to NRC, CNL-16-091, Proposed Technical Specifications (TS) Change TS-505 - Request for License Amendments - Extended Power Uprate (EPU) - Supplement 18, Responses to Requests for Additional Information and Updates Associated with Interconnection System Impact Study Modifications, dated May 27, 2016 (ML16197A563)

By the Reference 1 letter, Tennessee Valley Authority (TVA) submitted a license amendment request (LAR) for the Extended Power Uprate (EPU) of Browns Ferry Nuclear Plant (BFN) Units 1, 2 and 3. The proposed LAR modifies the renewed operating licenses to increase the maximum authorized core thermal power level from the current licensed thermal power of 3458 megawatts to 3952 megawatts. During the technical review of the LAR, the Nuclear Regulatory Commission (NRC) identified the need for additional information. The Reference 2 letter provided an NRC Request for Additional Information (RAI) related to dose analyses. The due date for the response to NRC RAI ARCB-DA-RAI 1.1, provided by the Reference 2 letter, is July 29, 2016. to this letter provides the response to NRC RAI ARCB-DA-RAI 1.1.

U.S. Nuclear Regulatory Commission CNL-16-118 Page 2 July 29, 2016 to this letter provides Revision 2 to the BFN EPU List and Status of Plant Modifications. The BFN EPU List and Status of Modifications is revised to reflect the response to NRC RAI ARCB-DA-1.1. Enclosure 2 supersedes and replaces Revision 1 of 7 of the BFN EPU LAR (Enclosure 10 of Reference 3) , dated May 27, 2016.

TVA has reviewed the information supporting a finding of no significant hazards consideration and the environmental consideration provided to the NRC in the Reference 1 letter. The supplemental information provided in this submittal does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards consideration . In addition, the supplemental information in this submittal does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed license amendment.

Additionally, in accordance with 10 CFR 50.91 (b)(1 ), TVA is sending a copy of this letter to the Alabama State Department of Public Health .

There are no new regulatory commitments associated with this submittal. If there are any questions or if additional information is needed, please contact Edward D. Schrull at (423) 751-3850.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 29th day of July 2016.

RJicttull(L J. :~~

Vice President, Nuclear Licensing

Enclosures:

1. Response to NRC Request for Additional Information ARCB-DA-RAI 1.1

2. BFN EPU LAR Attachment 47, List and Status of Plant Modifications, Revision 2 cc:

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant State Health Officer, Alabama Department of Public Health

ENCLOSURE 1 Response to NRC Request for Additional Information ARCB-DA-RAI 1.1

ENCLOSURE 1 ARCB-DA-RAI 1.1 In Section 2.9.2, Radiological Consequences Analyses Using Alternative Source Terms, of Attachments 6 and 7, Safety Analysis Report for Browns Ferry Nuclear Plant Units,1, 2, and 3 Extended Power Uprate, of the extended power uprate (EPU) LAR dated September 21, 2015, TVA stated, in part, that the effect of the proposed EPU on the radiological consequences of the loss-of-coolant accident (LOCA), fuel handling accident, control rod drop accident, and the main steamline break accident is based on an assessment of the effect of EPU changes on the dose consequence analyses that were evaluated by the NRC in the safety evaluation for the Browns Ferry AST License Amendments 251, 290, and 249, which approved a full-scope implementation of an AST that complies with the guidance given in RG 1.183 and 10 CFR 50.67.

By letter dated March 9, 2016 (ADAMS Accession No. ML16070A189), TVA responded to the RAIs associated with dose analysis. Specifically, the staff in ARCB DA RAI 1 asked that the licensee provide the current licensing basis (CLB) and the revised EPU input values, assumptions, and methods, as well as a justification for any changes to the CLB. The NRC also requested that the licensee identify which of these parameters were not previously reviewed and approved by the NRC and provide a justification for the change from the previously reviewed values to the CLB. TVA, in its response dated March 9, 2016, supplemented the above information with additional information regarding updates to the LOCA analyses. TVA in the RAI response stated, in part, that The LOCA analysis was subsequently [after approval of the AST] revised and approved in the license amendments issued for Technical Specification (TS) Change Request TS-474 [Amendment Nos. 282, 308 and 267 for Units 1, 2 and 3, respectively].

In the RAI response TVA did not discuss information regarding a non-conforming/degraded condition that impacts the design configuration and accident response reviewed and approved in the Amendment Nos. 251/282 (Unit 1), 290/308 (Unit 2) and 249/267 (Unit 3). However, in a letter dated May 26, 2016 (ADAMS Accession No. ML16148A108), TVA stated that it is expected to resolve the nonconforming/degraded condition during Refueling Outage 18 in Fall 2018 (Unit 1), Refueling Outage 20 in Spring 2019 (Unit 2), and Refueling Outage 18 in Spring 2018 (Unit 3).

E1-1

ENCLOSURE 1 TVA proposes to use the approval of Amendments 251/282 (Unit 1), 290/308 (Unit 2) and 249/267 (Unit 3) to justify the dose analysis at the EPU condition, but the design configuration and accident response assumed in these amendments does not exist due to a non-conforming/degraded condition. In order to determine that there is reasonable assurance that the acceptance criteria for the radiological consequences analyses for 10 CFR 50.67 and GDC 19 are met, the NRC staff asks TVA to provide either:

1. A license condition to "perform facility and licensing basis modifications such that the current licensing basis dose calculations would remain valid" prior to the implementation of the EPU, Or

2. Provide the following information.

a. Since the withdrawal of the LAR on May 29, 2015, what changes were made to the compensatory measures (including the dose analysis submitted to the NRC) to address the NRCs concerns with the LAR (as discussed in the March 18, 2015 meeting)?

b. Explain how the compensatory measures, discussed above, restored all applicable structures systems and components to operability/functionality such that they can perform their desired safety function.

c. With a nonconforming/degraded condition in the primary ALT flow path (that may not function during a LOCA due to valve(s) closing that may not be reopened) and considering a single failure in the secondary ALT flow path how are the safety functions of these ALT flow paths ensured?

TVA Response:

As part of the Extended Power Uprate License Amendments, Browns Ferry Nuclear Plant will accept license conditions for resolution of the Alternate Leakage Treatment pathway non-conforming/degraded condition worded as follows.

TVA shall perform facility and licensing basis modifications to resolve the non-conforming/degraded condition associated with the Alternate Leakage Treatment pathway such that the current licensing basis dose calculations (approved in License Amendment Nos. [251/282 (Unit 1), 290/308 (Unit 2) and 249/267 (Unit 3)]) would remain valid. These facility and licensing basis modifications shall be complete prior to initial power ascension above 3458 MWt.

E1-2

ENCLOSURE 2 BFN EPU LAR Attachment 47, List and Status of Plant Modifications, Revision 2

Browns Ferry Units 1, 2 and 3 EPU Modifications, Revision 2 The modifications required to support Extended Power Uprate (EPU) for Browns Ferry Nuclear Power Station (BFN) Units 1, 2 and 3 are shown in Table 1. The modifications reported as Complete in Table 1 are fully implemented, for all other modifications, a schedule for full implementation is provided. All EPU modifications, either completed or being prepared, are in accordance with the TVA Plant Modifications and Engineering Change Control process.

Further evaluations may identify the need for additional modifications or obviate the need for some modifications. As such, Table 1 listings are not a formal commitment to implement the modifications exactly as described or per the proposed schedule.

Additionally, various minor modifications and adjustments to plant equipment, which may be necessary, are not listed.

Att 47-1

Table 1: BFN EPU Planned Modifications and Current Schedule Scheduled Modification Description Completion (Note 1)

Replacement New steam dryers will be installed with increased structural design margin Unit 1 - Fall 2018 Steam Dryer to accommodate EPU operation. Unit 2 - Spring 2019 Replacement steam dryers are curved hood six-bank dryers analyzed Unit 3 - Spring 2018 for fatigue resulting from flow induced vibration and hydrodynamic loads.

Main steam line strain gages were previously installed to obtain measurements at CLTP conditions which were used to design the replacement steam dryers.

New main steam line strain gages will be installed to replace the existing strain gages which have reached end of life to obtain measurements during power ascension testing of the replacement steam dryers.

Main Turbine Replace the High Pressure Turbine rotor. Incorporate GE's Advanced Design Steam Path which is designed for the increased flow associated with EPU.

Unit 1 - Fall 2018 Replace High Pressure Turbine diaphragms and rotor buckets. Unit 2 - Spring 2019 Unit 3 - Spring 2018 Modify the cross around relief valves (CARVs) to permit increased set Unit 1 - Complete pressure. Unit 2 - Complete Unit 3 - Complete Replace and/or recalibrate Main Steam system flow and pressure Unit 1 - Complete instruments. Unit 2 - Complete Unit 3 - Complete Turbine Sealing Increase the size of the Steam Packing Unloader Valves (SPUVs) and Unit 1 - Complete Steam associated piping to enable the turbine sealing system to accommodate Unit 2 - Complete EPU flow requirements. Unit 3 - Complete Increase SPUVs and piping from 8-inch to 10-inch components.

Replace and rescale steam flow and steam pressure transmitters.

Att 47-2

Scheduled Modification Description Completion (Note 1)

Condensate Upgrade Condensate pumps with new impellers and motors to Unit 1 - Complete Pumps accommodate the increased flows that will be required for EPU operation. Unit 2 - Complete Replace impellers in each pump (3 pumps per Unit). Unit 3 - Complete Replace 900 HP motors with 1250 HP motors.

Add orifice plate to the Condensate Recirculation line to reduce pressure drop across the flow control valve to minimize cavitation and vibration.

Replace existing pump discharge check valves with different style check valves having lower pressure drop and better transient response.

Replace pump suction strainers with stronger mesh screen to prevent screen deformation with the increased EPU flow conditions.

Change motor protection relay settings.

Recalibrate/replace pump and motor instrumentation.

Condensate Replace the Condensate Booster (CB) pumps and motors to increase Unit 1 - Complete Booster Pumps pump capacity to accommodate the increased flows that will be required Unit 2 - Complete for EPU operation. Unit 3 - Complete Replace CB pumps with higher capacity pumps.

Replace air-cooled 1750 HP motors with water-cooled 3000 HP motors.

Replace existing pump discharge check valves with different style check valves having lower pressure drop and better transient response.

Change motor protection relay settings.

Recalibrate/replace pump and motor instrumentation.

Condensate Pump Provide additional cooling/ventilation in vicinity of the Condensate and Unit 1 - Complete and Condensate Condensate Booster pumps to accommodate the increased heat load Unit 2 - Complete Booster Pump resulting from larger air-cooled Condensate Pump motors and supplement Unit 3 - Complete Area Ventilation cooling requirements for the hydrogen water chemistry (HWC) main control panel.

Replace 3-position switches for operation of the Air Handling Units (AHUs) with 4-position switches that will allow parallel operation of the AHUs.

Addition of a balancing damper to the Condensate Pump motors to provide better balancing of air flow.

Addition of a branch duct and balancing damper to the HWC main control panel.

Att 47-3

Scheduled Modification Description Completion (Note 1)

Feedwater Pumps Upgrade the Feedwater system to provide increased Feedwater flow for and Turbines EPU operation.

Replace pumps with higher capacity pumps. Unit 1 - Complete Replace turbine rotor, diaphragms and buckets. Unit 2 - Complete Replace turbine/pump coupling. Unit 3 - Complete Upgrade seal water injection subsystem.

Update Feedwater control system software for EPU conditions. Unit 1 - Fall 2018 Unit 2 - Spring 2019 Unit 3 - Spring 2018 Moisture Modify the internals of the moisture separators to increase moisture Unit 1 - Complete Separators removal and accommodate increased flows at EPU conditions. Unit 2 - Complete Change vanes and added perforated plate on moisture separators. Unit 3 - Complete Modify internal drains as needed.

Feedwater Upgrade Feedwater Heaters to support EPU operating conditions.

Heaters Unit 1 - Complete Re-rate the number 1, 2 and 3 Feedwater Heater shells to meet higher Unit 2 - Complete pressures, temperatures and flows under EPU conditions by Unit 3 - Spring 2018 modification of selected nozzles and replacement of shell relief valves to meet ASME code requirements.

Replace level control instrumentation on the number 1, 2 and 3 Feedwater Heaters to reduce susceptibility to flow induced turbulence (pressure transients).

Provide additional welds and bracing to the pass partition plates for Unit 1 - Complete Nos. 1, 2, 3, and 5 Feedwater Heaters. (Number 4 Feedwater Unit 2 - Complete Heaters pass partition plates will be addressed with replacement of Unit 3 - Complete the tube bundle and channel head.)

Due to the increase in tube-side design pressure with the increase Unit 1 - Complete head capacity of the Condensate Booster pumps, replace channel Unit 2 - Complete head relief valves for No. 3 Feedwater Heaters with valves having Unit 3 - Spring 2018 higher setpoints, and install a reinforcement ring on the manways for the number 3 and number 5 Feedwater Heaters.

On each of the number 3 Feedwater Heaters, replace the upper shell Unit 1 - Complete and install an extraction steam inlet duct to minimize heater shell Unit 2 - Spring 2017 erosion and preclude tube damage from steam jet impingement. Unit 3 - Complete Replace tube bundle and channel head in the number 4 Feedwater Unit 1 - Fall 2018 Heaters with a design less susceptible to damage from flow induced Unit 2 - Spring 2019 vibration. Unit 3 - Spring 2018 Main Condenser Replace Main Condenser Extraction Steam bellows #2, #3, #4 and #5 with Unit 1 - Complete Extraction Steam bellows accommodating higher design temperatures and pressures for Unit 2 - Complete Bellows EPU. Unit 3 - Complete Att 47-4

Scheduled Modification Description Completion (Note 1)

Condensate Install a 10th condensate demineralizer (and associated valves and Unit 1 - Complete Demineralizers controls) on each unit to accommodate the increased condensate flow Unit 2 - Complete associated with EPU operation.

Unit 3 - Complete Steam Packing Increase the capacity of the steam packing exhauster bypass line to Unit 1 - Complete Exhauster Bypass accommodate increased flow under EPU conditions. Unit 2 - Complete Install larger piping and flow control valve. Unit 3 - Complete Torus Attached Modification to reinforce an existing pad at an ECCS ring header branch Unit 1 - N/A Piping connection to address higher pipe stresses associated with EPU Unit 2 - Complete conditions. Required only on Units 2 and 3 as sufficient stress margin Unit 3 - Complete exists on Unit 1.

Main Steam Modify one Unit 2 Main Steam pipe support due to increased loads Unit 1 - NA Supports resulting from turbine stop valve closure at EPU steam flow rates. All other Unit 2 - Complete existing Unit 2 Main Steam pipe supports, and all Main Steam pipe Unit 3 - NA supports on Units 1 and 3, were determined to have sufficient design margin to accommodate the increased turbine stop valve closure loads.

Reactor Upgrade the reactor recirculation system for EPU core flow operating Recirculation conditions.

Pumps & Motors Perform analyses/evaluations to increase the design ratings for the Unit 1 - Complete recirculation pumps and motors. Unit 2 - Complete Upgrade the Variable Frequency Drive (VFD) control system. Unit 3 - Complete Perform pump and motor instrumentation upgrades - jet pump head, RCW flow, motor winding temperatures, VFD protective relay settings.

Revise Upper Power Runback setting for EPU conditions. Unit 1 - Fall 2018 Unit 2 - Spring 2019 Unit 3 - Spring 2018 Jet Pump Sensing Install jet pump sensing line clamps to reduce pipe vibration under EPU Unit 1 - Complete Line Clamps conditions. Unit 2 - Complete Unit 3 - Complete Main Generator Uprate main generator to 1330 MVA (Unit 1) / 1332 MVA (Units 2 & 3). Unit 1 - Complete System Install rewound stator to support higher generator output capacity. Unit 2 - Spring 2019 Unit 3 - Complete Replace/modify stator water cooling (SWC) instruments and change SWC flow, pressure, DP and temperature settings to support increased stator water cooling requirements.

Main Generator Increase generator hydrogen pressure from 65 psig to 75 psig to support Unit 1 - Fall 2018 Hydrogen EPU operation. Unit 2 - Spring 2019 Pressure Change pressure regulating valve settings and pressure alarm setting. Unit 3 - Spring 2018 Replace pressure switches as needed for new operating range.

Change generator field over-excitation relay settings.

Eliminate hydrogen flow integrator to mitigate hydrogen leakage.

Att 47-5

Scheduled Modification Description Completion (Note 1)

Isophase Bus Duct Modify isophase bus duct cooling system to remove increased bus duct Unit 1 - Complete Cooling heat under EPU conditions. Unit 2 - Complete Replace cooling fans and motors. Unit 3 - Complete Replace cooling coils.

Main Bank Upgrade main bank transformers to account for the higher power output Unit 1 - Complete Transformers from the main generators at EPU conditions. Unit 2 - Complete Replace three 500 MVA transformers per unit. Unit 3 - Installation Replace one Units 1 and 2 500 MVA spare transformer. complete, post-Install new dedicated Unit 3 500 MVA spare transformer. modification testing of the Unit 3 Spare Transformer pending Vibration Install mounting brackets/supports and temporary instrumentation for Unit 1 - Fall 2018 Monitoring vibration monitoring during EPU power ascension in accordance with Unit 2 - Spring 2019 Attachment 45 (Flow Induced Vibration Analysis and Monitoring Program).

Unit 3 - Spring 2018 Main Steam Modify MSIVs to support steam flow increase at EPU conditions. Unit 1 - Complete Isolation Valves Install longer stroke actuators to move the poppet further out of the Unit 2 - Complete (MSIV) flow stream. This modification reduced valve pressure drop to Unit 3 - Complete accommodate EPU conditions.

Perform additional modifications to improve performance of the MSIVs including new bonnets, nose guided poppets (trimmed profile), and larger diameter valve stems.

Electro-Hydraulic Revise EHC software to address changes in plant parameters required to Unit 1 - Complete Control (EHC) support EPU.

Unit 2 - Complete Software Electrical Overspeed set point, Intermediate Pressure, Power Load Unbalance, Turbine First Stage Pressure, and Megawatt (MW) Control Unit 3 - Complete Technical Technical Specification Instrument respan and setpoint changes for EPU Unit 1 - Fall 2018 Specification Turbine 1st stage pressure scram bypass permissive setpoint change Unit 2 - Spring 2019 Instrument Main steam line high flow isolation channel respan Unit 3 - Spring 2018 Respan APRM flow biased and setdown instrument respan and setpoint change Balance of Plant Respan balance of plant (BOP) instruments for EPU. Unit 1 - Complete Instrument Update hydrogen water chemistry programmable logic controller (PLC) Unit 2 - Complete Respan software for control of hydrogen and oxygen injection at EPU. Unit 3 - Complete Replace and respan hydrogen water chemistry flow instruments.

Replace and respan extraction steam pressure instruments.

Replace and respan feedwater heater pressure and level instruments.

Recalibrate setpoints for reactor feedwater low suction and steam jet air ejector stage I/II/III low pressure switches.

Respan high pressure turbine exhaust intermediate pressure.

Replace and respan offgas condenser cooling water temperature instruments.

Att 47-6

Scheduled Modification Description Completion (Note 1)

Condenser Upgrade condenser instrumentation for improved reliability and Instrumentation performance monitoring under EPU conditions.

Replace/relocate condenser A/B/C hotwell pressure transmitters to Unit 1 - Complete improve inputs to the integrated computer system (ICS).

Add condenser circulating water (CCW) inlet/outlet temperature inputs Unit 2 - Complete to the integrated computer system (ICS). Unit 3 - Complete Respan condenser A/B/C CCW outlet flow channels and add to ICS.

Revise reactor feed pump turbine (RFPT) trip to two out of three logic.

Modify Steam jet air ejector (SJAE) to remove the trip on low condenser vacuum and eliminate auto-start of standby SJAE.

Install nine new condenser vacuum pressure transmitters per unit (3 on each condenser) and provide signals to electro-hydraulic control Unit 1 - Fall 2018 (EHC) system. Unit 2 - Spring 2019 Move condenser A/B/C low vacuum alarm, low vacuum turbine trip Unit 3 - Spring 2018 and low vacuum bypass trip functions to EHC logic (previously performed by pressure switches).

Perform hardware and software changes to EHC system to support new alarm and trip functions.

Steam Jet Air Revise setpoints for SJAE condensate pressure switches to prevent Unit 1 - Complete Ejector (SJAE) inadvertent SJAE isolation. Unit 2 - Complete Pressure switches Unit 3 - Complete Main Steam Install Acoustic Vibration Suppressors (AVS) inside the Main Steam 6" Unit 1 - Complete Acoustic Vibration diameter blind flanged branch lines to reduce acoustic loading on the Unit 2 - Complete Suppressors steam dryer.

Unit 3 - Complete Standby Liquid The shutdown capability of the SLC system is being increased to support Unit 1 - Fall 2018 Control (SLC) the Containment Accident Pressure Credit Elimination during an ATWS Unit 2 - Spring 2019 System event as discussed in PUSAR Section 2.8.4.5.3 (Attachment 6) by Unit 3 - Spring 2018 increasing the Boron-10 enrichment.

Emergency High As part of the transition to National Fire Protection Association Standard Unit 1 - Fall 2016 Pressure Makeup (NFPA) 805, BFN is installing a non-safety related emergency high Unit 2 - Spring 2017 Pump pressure pump in each unit to provide makeup from the Condensate Unit 3 - Spring 2018 Storage Tank to the Reactor Pressure Vessel. This modification is not required for EPU operation but is addressed in PUSAR Section 2.6.5.2 (Attachment 6), Containment Accident Pressure (CAP) Elimination.

Although not needed for CAP Credit Elimination, use of the makeup pump will provide additional NPSH margin during the Fire Event.

Att 47-7

Scheduled Completion Modification Description (Note 1)

Emergency High As part of the transition to National Fire Protection Association Unit 1 - Fall 2016 Pressure Makeup Standard (NFPA) 805, BFN is installing a non-safety related Unit 2 - Spring 2017 Pump emergency high pressure pump in each unit to provide makeup from Unit 3 - Spring 2018 the Condensate Storage Tank to the Reactor Pressure Vessel. This modification is not required for EPU operation but is addressed in PUSAR Section 2.6.5.2 (Attachment 6), Containment Accident Pressure (CAP) Elimination. Although not needed for CAP Credit Elimination, use of the makeup pump will provide additional NPSH margin during the Fire Event.

Hardened Wetwell In response to EA-13-109, Order Modifying Licenses with Regard to Unit 1 - Fall 2016 Vent Reliable Hardened Containment Vents Capable of Operation Under Unit 2 - Spring 2017 Severe Accident Conditions, the Hardened Wetwell Vent (HWWV) Unit 3 - Spring 2018 will be modified to provide individual vent lines for each BFN unit.

As discussed in PUSAR Section 2.6.1.4 (Attachment 6), the existing HWWV capacity would be reduced to 0.88% of rated thermal power under EPU conditions. However, with the implementation of this modification in response to EA-13-109, the capacity of the HWWV will be restored to 1% of EPU thermal power.

Static Excitation As a result of the increased electrical generation at EPU, the Unit 1 - Fall 2020 System Excitation System on Units 1, 2, and 3 will be upgraded by installing Unit 2 - Spring 2023 a Static Excitation System. The system will include a dual channel Unit 3 - Spring 2024 digital automatic voltage regulator (AVR) for complete redundancy, with each channel consisting of an auto and manual back-up mode.

(See also Note 2 below.)

Alternate Leakage Provide a highly reliable Alternate Leakage Treatment Pathway that Unit 1 - Fall 2018 Treatment routes 99.5% of the leakage from the primary containment MSIVs Unit 2 - Spring 2019 Pathway directly to the condenser. The modification on each unit will include Unit 3 - Spring 2018 replacement of five motor operated valves on the Main Steam drain lines with air operated valves. Also, an additional Main Steam drain line valve will be installed, with an air operator, to address single failure criteria. All the new air operated valves will fail open on loss of electrical power or control air.

Notes:

1) The expected completion timeframes reported in Table 1 correspond to the following refuel outages: For BFN Unit 1, Fall of 2016 is RFO-U1R11, Fall of 2018 is RFO-U1R12 and Fall 2020 is RFO-U1R13. For BFN Unit 2, Spring of 2017 is RFO-U2R19, Spring of 2019 is RFO-U2R20 and Spring 2023 is RFO-U2R22. For BFN Unit 3, Spring of 2018 is RFO-U3R18 and Spring 2024 is RFO-U3R21.

2) The Static Excitation System is not required to be installed prior to EPU operation. During the interim period of EPU operation preceding installation of the Static Excitation System, transmission system grid stability will be maintained through use of a detailed temporary operating guide.

Att 47-8